In machines of this type that are already known, the closing section is normally moved angularly so that it has a closed and an opened position. In this type of machine the untreated tires are loaded manually or by means of external loading devices that are separate from the machine itself.
Manual loading obviously involves high plant management costs, and when devices that are separate from the machine are provided for loading the untreated tires, plant costs are high and a great deal of floor space is required. In any event, these known types of machines create functional problems. In fact the untreated tire that is loaded into the open mold is left free until the upper part of the mold is lowered to close it. This involves the risk of the untreated tire being misaligned inside the mold before it is closed. This chiefly arises because the untreated tire is particularly unstable and easily deformed. If the tire warps when it is resting on the bottom section of the mold and before the top section of the mold is closed, defects will occur during vulcanization and there will be rejects, with the resultant effects on production costs.